Piston



S. OTSU.

PISTON.

APPLICATION FILED JUNE 27,1917.

1,371, 10 Patented Mar. 8,1921.

2 SHEETS-SHEET 1.

31 W WLJM s. OTSU.

PISTON.

APPLICATION FILED .IUNE27, 1917.

1,371,108. Patented Mar. 8,1921.

7 2 SHEETS-SHEET 2.

UNITED STATES PATENT OFFICE.

SHINTABO OTSU, 0F OSAKA, JAPAN, ASSIGNOR TO KABUSHIKI KAISHA OSAKA TEKKOSHO, OF OSAKA, JAPAN, A CORPORATION OF JAPAN, DOCK Y PISTON.

Specification bf Letters Patent.

Patented Mar. 8, 1921.

.hole decreasing its sectional area gradually toward the outer edge is made between the edges of a packing ring which is fitted into a groove on the circumferential face of the piston, and a wedge-shaped piece of corresponding shape, being pressed out from its back by means of a helical spring or the like, is secured into the hole.

The invention has for its object not only to press out a packing ring to a cylinder-wall but to distribute pressure in every direction .and thus to absolutely prevent the leakage of steam in order to increase efficiency and durability.

In.the accompanying drawings: Figure 1 shows a sectional elevation of an example of a piston relating to the invention; Fig. 2 is a plan of the same omitting some parts; Fig. 3 is a side view showing the section of part of a packing ring; Fig. 4 is a plan of a part; Figs. 5 to 7 are side views, showing some parts of the piston; Fig. 8 is a fragmentary sectional elevation showing one of the adjusting plates in position. Similar letters refer to similar parts throughout the several views.

(a) is a packing ring, which is applied into a groove (d) formed between the iston-body (b) and a junk ring (a), an it may be separated intotwo or more segments along its circumference and also into two parts, up and down or axially, and the contacting edges (6) and overlap each otheror are so made as to prevent leakage by some proper method.

At a certain position between the contact- 7 ing edges (6) and (f), a wedge-shaped hole (g) of square, circular or some other form of section is made, into which a wedge (h) of corresponding shape is fitted. is a helical spring, put in a recess (j) made in the piston body, keeping its position by means of a holder (is), which presses the wedge (h) toward the cylinder wall. (m) is a stoppenfixed to the piston body (1)), and its pro ection (m) is fitted into a groove (a) which is made on the inner face of the packing ring (0.), thus it prevents the packing ring from turning around the piston body and also from changing rela tive position of the wedge (h) and the spring (2').

(a) is a junk ring which serves to hold the packing ring at its proper position; (0), a ring conveniently made to adjust the position of the packing ring (0;) by somewhat press ng it before fixing the junk ring (0) (p) is a packing material of soft metal applied to a recess between the wedge (h) and packing ring (a), in order to relieve the wearof their contacting surface.

With the piston of the invention, tightness between the cylinder wall and the packing ring (a), or that of between the both contacting edges (f) of the packing ring (a), or that between the packing rings (a) and the side walls of the groove (d), is perfectly maintained, since the packing ring (a) gives pressure in every direction by the action of wedge (h) which is placed between every two segments of the packing ring (a), and which is pressed by the spring (2') from its back. As the leakage of steam in every part is thus prevented absolutely, the work of the piston is most effectual.

In almost all the packing rings in pistons which are already known, pressure acts only radially, the tightness of their contacting edges and that of the space between the two sides of the rings and the side wall of the grooves being impossible to be kept perfect. So, when steam begins to leak it can not be repaired and the rings are to be replaced anew. But in this invention, the wedge (h) being made to be pressed up as the circumferential face of the packing rings and their contacting edges'wear themselves off, tightness is always kept uniform and in consequence the piston works most effectually.

If the spring which presses the wedge has become non-effective by being elongated beyond its elastic limit or by some other causes, its usefulness can easily be restored by applying a thin plate (r) between the spring (2') and body of the piston through a peep hole (0) bored in the ring (0) after taking off the cover (0).

On the whole, the principle of the invention lies in the fact that the segments of a packing ring are subjected to pressure radially toward the cylinder wall and also circumferentially, by means of a wedge (11) applied into a proper bore with decreasing section toward the outer circumference of the packing ring made between the contacting edges of each segment of the packing ring, and pressed internally by means of a spring (2'). Thus the tightness-of the other parts of the piston and that of the space between the cylinder wall and the packing ring, to which attention has not been duly paid hitherto, is kept perfect, and the results are the increased efliciency of the piston and the saving of much trouble and cost of replacing of the various parts of the same in order to prevent steam leakage.

This invention can be modified as far as it is compatible with the above-mentioned principle.

Having thus described my invention, what and means in said recesses for exerting.

pressure against said segments circumferentially and axially of the piston.

3. A packing ring comprising, in combination, a plurality of segments havingover-- lapping parts provided with registering recesses at the joints therebetween so shaped as to form outwardly tapering holes, wedges fitting in said holes and adapted to exert pressure against said segments in radial, circumferential and axial directions, and

means pressing said wedges radially outin said holes.

wardlly 4. piston comprising, in combination,

of packing segments ad olnlng a plurality one another circumferentially and axially and having registering recesses at the joints therebetween so shaped as to form outwardly tapering sockets, wedges fitting in said sockets and adapted to exert pressure radially, circumferentially and longitudinally of the piston, means pressing said wedges radially outwardly, and means limiting the circumferential movement of said segments.

5. A piston comprising a body, a junk ring or clamping member, and a plurality of segments disposed between said body and ring and adjoining one another axially and circumferentially, said segments having registering recesses at the joints therebetween so shaped as to form outwardly taper: ing holes, wedges fitting in said holes and adapted to exert pressure against said segments radially, circumferentially and axially of the piston, resilient means bearing against said wedges, and devices adapted to be inserted between said resilient means and the piston body for increasing the tension of said resilient means.

6. A piston comprising a body, a junk ring or clamping member, a plurality of seg;

ments disposed between said body and-ring,

devices for exerting pressure against said segments, and a plate between said junk ring and said pressure exerting devices having openings therein through which said pressure exerting devices are accessible.

7. The combination with a plurality of sectional packing rings having overlapping circumferential edges and overlapping ends provided with registering recesses, of means engaging in said recesses for exerting pressure radially and axially of said rings.

In testimony whereof I hereunto aflix my signature.

SHINTARO OTSU. L. s.] lVitnesses:

W. EBIHARAH, S. MA'ISUDA. 

